Methods of processing wool and other hair fibers



iii-1.07

United States Patent fice ans-ado Emir Hummus.

3,434,795 Patented Mar. 25, 1969 Int. Cl. D06m 3/02 US. Cl. 8l27.6 6 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to the Wet processing of wool and other hair fibers in the presence of an hydroxylamine salt of a strong mineral acid, for the purpose of eliminating the natural yellowish cast characteristic of such fibers which often become more pronounced in high temperature dyeing procedures and in processing such fibers under alkaline conditions.

This invention relates to' methods of processing wool and other hair fibers and to hair fibers treated by such methods. The invention is particularly concerned with the wet processing of hair fibers.

It is 'a matter of general knowledge that all hair fibers, whether their origin be sheep, camels, goats or other animals, possess to a greater or lesser extent a yellowish cast or ,colo'ration when they are removed from the body of the animal and initially processed. This yellowish cast becomes more pronounced during high temperature dyeing procedures, particularly when the dyeing temperatures are in the range of 200 F. to 212 F. Yellowing also increases when the hair fibers are subjected to alkaline processing, particularly when the processing takes place at temperatures above 190 F.

Conventional reducing agents, such as sodium bisulfite, sodium or zinc formaldehyde sulfoxylate, or sodium or zinc hydrosulfite, lighten the wool, but this effect is only temporary; furthermore, these reducing agents react with Wool dyes and strip them from the fibers.

An object of the present invention is to provide a method for wet processing of wool and other hair fibers in which the effect of overcoming the yellowish cast will be durable and which will not afiect disadvantageously the hand orctzharacter of the wool.

Anotherfobject is to provide a wet processing system for treating wool and other hair fibers wherein the tendency of "the yellowish cast or coloration to increase will be eliminated entirely and on the contrary the fibers will be lightened and brightened.

Other objects of the present invention will become apparent in the course of the following specification.

The present invention is based to a substantial extent on the surprising discovery that a hydroxylamine salt of a strong acid such as the sulfate or chloride, is most effective for this purpose.

Extensive experimentation has shown that hydroxylamine salts of strong acids while being definitely reducing agents, 'act differently from other conventional reducing agents when applied to animal fibers, such as wool. Hydroxylamine salts were found to have the unique property of lightening and brightening wool and other hair fibers without destroying the dyes. The effect produced is durable and long lasting. Apparently this is caused by the fact that these compounds act only on the wool substrata.

According to the present invention the preferred salts are mineral acid salts of hydroxylamine, such as the sulfate and the chloride.

In a preferred embodiment of the invention the salt used is hydroxylamine sulfate which is available com mercially in highly concentrated form, namely, in to 97% concentration with two mols of hydroxylamine combined with one mol of sulfuric acid.

It was found that hydroxylamine salts may be used in the dye bath together with wool dyes and that one operation is sufficient to accomplish the brightening or whitening of the wool, as well as the dyeing.

This contrasts remarkably with prior art procedures for obtaining bright pale shades of wool in which wool had to be bleached with hydrogen peroxide in a separate oper= ation before dyeing. This operation is not only costly but also has a tendency to damage the wool since it is carried out in an alkaline medium.

According to the present invention the concentration in the bath may vary from 0.015% to0.5% and the processing may take place at a pH of 2.0 to 7.0.

According to a preferred embodiment hydroxylamine sulfate is used in the amount of from'0.015% to 0.1% of bath volume and at a pH of 3.5 to 4.5.

The use of hydroxylamine sulfate and other mineral acid salts in the dye bath improves the light fastness of the dyed wool.

This treatment minimizes the tendency of the dyed shade to change toward red, commonly referred to as red fade, when exposed to sunlight or in the Fade-o-meter.

There is, however, a disadvantage in the use of a hydroxylamine salt in the dye bath, in that there is a tend= ency toward unlevel shades when dyeing pale shades (0.1%-0.25% OWF) with milling or neutral premetallized dyes. These dyes usually have a high rate' of ex 7 haustion at a low pH in the range of 3.05.0, which is the range usually encountered when hydroxylamine salts are present in the bath. Furthermore, hydroxylamine salts of strong acids are quite corrosive to'ordinary steel dyeing kettles and storage containers.

To overcome this corrosive effect it has been found that small amounts of ammonium, sodium "and potassium salts of phosphoric acid are very useful in inhibiting corrosion effects resulting from the use of hydroxylamine salts even though the pH of the treating bath be as low as 3.0. These phosphate salts also act as buffers in acid media and. fur= thermore provide level dyeings even in pale shades.

Also it has been found that the use of ammonium silico-= fluoride or other water soluble silicofiuerides in combina= tion with the hydroxylamine salts, enhance the brighten= ing elfect on wool or other hair fibers in the dyeing process.

In general, sodium sulfate, sulfuric acid, a silicofluoride and a phosphate may be added to the hydroxylamine for the processing operation.

The following examples are given solely by way of illustration and not by way of limitation.

Throughout the following examples the percentages of chemicals and dyes used in the dye bath are based on the weight of the fiber.

EXAMPLE I A 30:1 bath was prepared with 10% sodium sulfate, 1% acetic acid (50% and 4% of the following product:

- Parts Hydroxylamine sulfate 40 Ammonium silicofluoride we 20 Disodium phosphate 4...-.. 40

Scoured wool/worsted fabric was entered at F. and the bath was heated gradually to the boil and the boiling continued for one hour. The bath was cooled, dropped, and the fabric rinsed thoroughly and dried.

Wnzn'uumuuq IIWWINI A control sample was treated at the same time using the same procedure, but omitting the product of this invention. The sample treated with the product of this invention was much lighter and brighter than the control sample.

EXAMPLE II A 30:1 bath was prepared at 100 F. with anhyrdous sodium sulfate, 2% sulfuric acid, and 3% of the following product:

Parts Hydroxylamine sulfate 50 Disodium phosphate 10 Monosodium phosphate 40 sulfate, 2% ammonium sulfate, and 2% of the following product:

Parts Hydroxylamine sulfate 50 Ammonium silicofluoride 20 Disodium phosphate 20 Monosodium phosphate 10 Scoured wool/worsted fabric was entered into bath and worked for ten minutes. Then 0.1% 0.1. Acid Blue 80 was added and the bath brough gradually to the boil and the boiling continued for 45 minutes.

The dyeing is much brighter than a control dyeing carried out without above product.

EXAMPLE IV A 25:1 bath was prepared at 100 F. with 5% sodium sulfate, 1% acetic acid (50%), and 1.5% of the following product:

Parts Hydroxylamine sulfate 60 Diammonium phosphate 20 Monosodium phosphate M. 5 Ammonium silicofluoride l5 Prescoured worsted yarn was entered into this bath and run for ten minutes. Then 0.1% CI. Acid Blue 78 was added to bath and it was gradually heated to boil and boiled for one hour. The bath was then cooled, dorpped, the yarn was rinsed thoroughly and dried.

This dyeing is much brighter and clearer than a control dyeing carried out simultaneously.

EXAMPLE V A 25:1 bath was prepared at 105 with 10% sodium sulfate, 2% formic acid (90%.), and 1% of the followmg product:

Par-ts Hydroxylamine sulfate 50 Disodium phosphate 20 Monosodium phosphate -l0 Magnesium silicofluoride ....u 20

Prescoured carpet yarn was entered into this bath and run for ten minutes. Then 0.1% Brilliant Alizarine Light Blue 3F was added. The bath was brought to a boil and the boiling was continued for 45 minutes. The bath was then cooled, dropped and the yarn rinsed thoroughly and dried.

This dyeing was also brighter and bluer than a control dyeing which was carried out at the same time.

EXAMPLE VI A 30:1 bath was prepared at 100 F. with: 10% sodium sulfate, 2% ammonium sulfate, and 1.5% of the composition described in Example. III.

The prescoured wool/worsted fabric was entered and run for ten minutes. Then 0.1% C.I. Acid Brown was added. The bath was heated to 190 F. and the dyeing continued for one hour at this temperature.

The bath was cooled, dropped, and fabric was rinsed thoroughly and dried. The dyed sample was considerably brighter than a control sample.

EXAMPLE VII A 25:1 bath was prepared at 100 F. with: 10% sodium sulfate, 2% ammonium sulfate, and 2% of the composition described in Example II.

Then 0.05% Irgalan Brown Violet DL '(Geigy) (no color index designation being available), was added. A fabric consisting of 60% wool/40% mohair was entered and was run for ten minutes. The bath was brought gradually to the boil and the boiling continued for 45 minutes. The bath was then cooled, dropped and the fabric rinsed thoroughly and dried. This fabric was considerably brighter than a control dyeing.

EXAMPLE VIII A 25:1 bath was prepared at 100 F., with 10% sodium sulfate, 2% sulfuric acid, and 2% of the following product:

Parts Hydroxylamine sulfate 55 Disodium phosphate 5 Monosodium phosphate 20 Sodium sulfate 20 Scoured worsted yarn was entered and worked in the bath for ten minutes. Then 0.015% CJI. Acid Red I was added and dyeing continued according to Example VII. This dyed sample was considerably brighter than a control.

EXAMPLE IX Scoured wool fiannel was entered into a 30:1 bath which contained 10% sodium sulfate, 2% formic acid and 1% of the following product:

Parts Hydroxylamine chloride 75 Monosodium phosphate 20 Disodium phosphate 5 After running for ten minutes, 0.1% (LI. Acid Blue 78 was added and the dyeing continued as in Example VII. Resulting dyeing was brighter than the control.

EXAMPLE X Peroxide bleached wool vs. wool treated as in Example III.

(a) A piece of scoured wool/worsted flannel was sub jected to a full bleach as follows: A 25:1 bath was prepared at F. with a 0.25% (on weight of bath) tetra= sodium pyrophosphate and three volumes of hydrogen peroxide. Flannel was entered and was bleached for two hours at this temperature. Flannel was rinsed thoroughly, neutralized with 2% (OWF) acetic acid (50%) and then dried.

(b) Another piece of above flannel was treated as follows: a 25:1 bath was prepared at 105 F. with sodium sulfate, 1% (OWF) acetic acid, and 3% of the product of Example H 1.

Bath was brought to boil and boiled for one hour. The bath was cooled, then dropped and fabric rinsed thoroughly and dried.

(c) A piece of the same flannel was treated as in (b) except that the hydroxylarnine of Example III was omitted. Sample (b) was much whiter than sample (c), although not as white as sample (a).

When all three samples were exposed to 40 hours in the Fade-o-meter, the bleached sample (a) acquired about the same yellow color as the unbleached sample (0). Sample (b) yellowed only imperceptibly.

EXAMPLE XI A 30:1 bath was prepared at 110 F. with 10% sodium sulfate, 4% sulfuric acid, and. 1% of product of Example V-II'I.

Scoured carpet yarn was entered into bath and was worked in the bath for ten minutes. Then 0.1% CI. Acid Blue 158 (A.M.) was added. The bath was brought to boil within 25 minutes and the boiling continued for 45 minutes. The bath was then. cooled, dropped and the yarn rinsed thoroughly and dried. The dyed yarn was considerably brighter than a control dyeing which was dyed without hydroxylamine.

What is claimed is:

1. A method of wet processing wool and other hair fibers, which comprises processing the hair fibers in the presence of hydroxylamine which is in the form of a strong mineral acid at a pH of 2.0 to 7.0 in amounts from 0.015% to 0.5% of the bath.

2. A method of wet processing wool and other hair fibers in accordance with claim 1, wherein the processing also takes place in the presence of a water soluble silicofluoride and a alkali metal phosphate.

3. A method of wet processing wool and other hair fibers in accordance with claim 1, wherein the processing also takes place in the presence of sodium sulfate, sulfuric acid, a silicofl oride and a phosphate.

4. W001 fibers treated in accordance with the method described in claim 1.

5. A method of wet processing wool and other hair fibers, which comprises processing the hair fibers in the presence of hydroxylamine sulfate in the amount of from 0.015% to 0.1% of bath volume at a pH of 3.5 to 4.5.

6. A method of wet processing wool and other hair fibers in accordance with claim 5, wherein the processing also takes place in the presence of a silicofiuoride using 4 to 5 parts and an alkali metal phosphate using 4 to 10 parts, to 10 parts of the hydroxylamine sulfate.

References Cited UNITED STATES PATENTS 2,382.632 8/1945 Hessel et a1. 8127.6 2,545,450 3/1951 Dalton et a1 8127.6 X-R 3,282,639 11/1966 Lundgren et al. 8-127.6

MAYER WEINBLATT, Primary Examiner.

US. Cl. X.R. 8l07, 128, 133 

